Improved peocess fob converting ieon into steel



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THOMAS J. BARRON, OF BRO ()KIiYN, NEW YORK. Letters Patent .No. 60,823, dated January 1, 1867.

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TO ALL WHO IT MAY OONOERN:,

Be it known that I, THoMAs J. BARRON, of Brooklyn, in the county of. Kings, and State of New York, have invented anew and improved Method or Process of Converting Iron into Steel; and I do hereby declare that the following isa full, clear, and exact description thereof, and of its mode or manner of operation.

My invention or discovery consists in converting iron into steel, after the metal is formed or fashioned into any shape desired or required, and more or less deeply, as found useful or necessary, by the application of certain gases brought in contact with the metal while hot, and acting in combination with any suitable apparatus for heating such metal. The gases used by me for such purpose of converting iron into steel are carburetted hydrogen in combination with nitrogen or cyanogen separately or together, or carburetted hydrogen with nitrogen and carbonic oxide. Ammoniacal. gas and chlorine may also be used in the place of or mixed with the nitrogen.

The manner of applying these gases and carrying out my invention is substantially as follows: I construct a furnace to contain one or more ovens, muiiles, or. rctorts, of such form as to be adapted to receive the iron which it is desired to convert either partially or wholly into steel. Such rotorts are to be brought to a bright red or white heat according to the character of the steel to be produced, when the iron is placed into them and the retort closed. Into such retorts there is then forced or caused to enter, in immediate contact with the iron or metal, a mixture of carburetted hydrogen and nitrogen or cyanogen gas, or of carburettcd hydrogen and nitrogen acid, carbonic oxide gas, and either with or without gases derived from the compounds of ammonia. The carburetted hydrogen may be prepared in a separate retort in the usual manner, or may be generated in the retort containing the metal to be steeled, by slowly admitting into such retort either liquid hydro-carbons, solid hydrocarbons, or nitrogenized or other fats, which will be decomposed by the heat of the retort and converted into gas- The nitrogen, is prepared in the usual manner and is then forced into the retort in connection with the carburetted hydrogen. A proportion of from one-sixth to one quarter of nitrogen gas to five-sixths or three-quarters of carburetted hydrogen, will be found suflicient in ordinary cases to produce the result desired; but a larger proportion of nitrogen may be used, provided it is not so great as to drive the hydro-carbon from the surface of the metal, the surplus of the gases not taken up by the iron producing no injurious efl'ect. except perhaps a cooling eii'ect upon the heat of the retort, and passing out of the muflie. Cyanogen gas, which is composed of nitrogen and carbon may be used in place of pure nitrogen, but in such case a little greater propor tion of cyanogen than of nitrogen should be used or. mixed with the carburetted hydrogen. The gases formed by the decomposition of the muriate or other salts of ammonia, or of any substance that will produce such gases, may also be used in place of the nitrogen or in connection with it; the latter I deem the most preferable form of use. A compound or mixed gas composed of nitrogen and carbonic oxide, with asmall proportion of cyanogen and produced by passing atmospheric air through anair-tight retort, filled with charcoal, coke, or other fuel, and heated to ignition, may also be used in combination or connection with the carburettedhydrogen, and from the nitrogen and carbon contained in it, will be equally efficacious in producing the result mentioned, From the -facility and cheapness with which such mixed gas is produced, I generally makeuse of it. Articles, which it is desired to coat with or convert into steel, are allowed to remain in the bath of" gases a longeror shorter time according to the depth of the steel surface reqniredor desired, and the degree of heat to which they are subjected in the retort. With a low degree of heat, a longer time is required to steel the metal to a given depth, and the greater the heat, the quicker the actionof the gases, and the higher the steel. The time occupied inthe process varies from a few seconds'to a number of hours, five or six or more in some cases, according-to the depth to which it is desired to steel the metal, and the character,- andsize, and thickness of the iron, and the heat of the fui'nace. I have converted-ironnne-sixteenth of an inch thick into good steel in three minutes, and half an inch thick by two inches wide, in one and a half hours. If the heat is high enough, iron will be converted into steel an eighth of an inch deep, in from five to ten minutes, and in a much less time when the metal is near a welding heat; but with such extreme heat, the metal becomes coarse and requires reworking. What will be a sufficient time in any case and under different circumstances, can be easily determined by the operator by one or two preliminary trials.

When the iron to be coated with or converted into steel is impure, chlorine gas should be admitted into the retort previous to the admission of the carburetted hydrogen and other gases, and should remain in contact with the metal a few minutes or longer time, according to the quality of the iron. Such gas has the effect to carry oil or take up any impurities, as they are volatilized, which may have been contained in the metal. Such gas may be prepared and forced intdthe retort, or generated therein, as'found most convenient. When the iron is pure, the use of theehlorine gas may be dispensed with. When the metal has been suiliciently acted on by the gases, in the hottest part of the retort, it may be removed to the end or cooler part of the retort, or to another retort connecting therewith and extendiiigbeyond the heat of the fire, and there retained in the bath of gases until it is sufficiently coolto prevent oxidation when it comes in contact with the atmosphere. This manipulation or removal is made when the metal or articles steeled do not require hardening. When any such articles require hardening the retort connects with or opens into, the hardening bath, into Which the articles are dropped ivithout exposure to t he'atniosphere. When the retort cannot be connected with the hardening-bath, a jet of the gases should be playedupon the metal or articles as they are removed from the retort to the hardeninghath, so as to form an atmosphere of gas around'them to prevent oxidation. This shielding of the articles from contact with .the atmospherein passing from the retort to the hardening bath, prevents oxidation or discoloration of the surface, and is especially desirable and useful when the article hasbeen polished or finished before being steeled, and it is desired to preserve perfect the finished or polished surface. The retort-s containing the metal or articles to be steeled, are ventilated so as to allow the gases to escape therefrom, and fresh gas to enter. or be generated therein, or a discharge-pipe may be connected therewith which will conduct the gases passing out of theretort intothe fire, where they can be burned as fuel.

What I claim a's my invention, and desire to secure by Letters Patent, is-

1.' The use and application, for converting iron into steel, of the compound gas, composed of carburetted hydrogen with nitrogen and cyanogen, or with nitrogen and carbonic oxide, and either with or without ammoniacal and chlorine gases, applied substantially as described.

2. The use, in combination with the process of converting ironinto steel by the application of such gases, of chlorine gas, preliminary to such process, for the purpose and in cases as set forth.

'3. Protecting the metal, after'it has been s teeled or converted into steel, and when the same is to be hardened While being transferred to the 'hardening bath from contact with the atmosphere, for the purposes set forth. i I

THOS. J. BARRON.

Witnesses:

S. D. LAW, W. R. Bron. 

